TKI258, an oral multitargeted receptor tyrosine kinase (RTK) inhibitor is known to potently inhibit the class III, IV, and V RTKs, showing biochemical 50 percent inhibitory concentration(IC50) values <20 nmol/L for VEGFRs (VEGFR-1, VEGFR-2, and VEGFR-3); the platelet-derived growth factor receptor-β (PDGFR-β); fibroblast growth factor receptors 1, 2, and 3 (FGFR-1,2,3); fetal liver tyrosine kinase receptor 3 (FLT-3); and KIT Ret, tyrosine kinase A (TrkA), and csf-1 RTKs. Due to the unique inhibitory activity on FGF pathways, TKI258 has shown significant activity in a variety of tumor xenograft models in athymic mice, including acute myeloid leukemia, multiple myeloma, and colon- and prostate-derived models9.